1. Field of Invention
The present invention relates generally to the field of communications. More specifically, the present invention is related to a system and method for circuit emulation service (CES) over IP.
2. Discussion of Prior Art
There are a variety of communicating means associated with networks today including, but not limited to: T1, T3, E1, or E3. A brief description of each of the following is given below:
T1: A dedicated network connection supporting data rates of 1.544 Mbits per second. A T-1 line actually consists of 24 individual channels, each of which supports 64 Kbits per second. Each 64 Kbit/second channel can be configured to carry voice or data traffic. Network companies lease out some of these individual channels, and this network connection is known as fractional T-1 access. T-1 lines are sometimes referred to as DS1 lines.
T3: A dedicated network connection supporting data rates of about 43 Mbps. A T-3 line actually consists of 672 individual channels, each of which supports 64 Kbps. T-3 lines are sometimes referred to as DS3 lines.
E1: Similar to the North American T-1, E1 is the European format for digital transmission. E1 carries signals at 2.048 Mbps (32 channels at 64 Kbps), versus the T1, which carries signals at 1.544 Mbps (24 channels at 64 Kbps).
E3: European digital signal 3 is another European format for digital transmission. E3 carries 34.368 Mbps with about 480 channels.
The present communications revolution has focused on the Internet and World Wide Web (WWW) with emphasis on the Internet protocol (IP). The high-speed IP-based networks based on connections described above are the latest innovation in the world of communications. The capacity of these networks is increasing at a prodigious rate, fueled by the popularity of the Internet and decreasing costs associated with the technology.
Circuit emulation over IP permits mapping of T1/E1 traffic (as well as a variety of other constant bit rate digital signals traffic) onto IP packets to be transported over a backbone IP network (like the Ethernet). None of the systems available today, however, teach a viable solution to handling circuit emulation service (CES) over Internet Protocol (IP).
Each of the below-described references teaches methods of circuit data transmission in prior art communication systems. However, none of the references provide or suggest the present invention method of circuit emulation service over IP.
U.S. Pat. No. 5,274,635 discloses a method for circuit alignment when circuit data is transmitted over a cell-based network. The data contained in the cells is arranged in either a bit-skewed arrangement or byte-skewed arrangement dependent on whether or not the data is simple DS0 data or bundled DS0 data. The skewed arrangements are utilized in conjunction with an alignment bit in the header, which is set when the cell contains an aligned timeslot, to provide circuit alignment. IP networks do not appear to be explicitly disclosed.
U.S. Pat. No. 5,987,030 describes a system that utilizes frame count values and two offset values placed in the header to recreate temporal locations of circuit data transmitted over a packet network. IP networks do not appear to be explicitly disclosed.
The European patent EP0722237A1 describes in the background, the transmission of an entire frame including the synchronization channel over a packet network to correctly position circuits when all of the incoming circuits are to be transported to the same destination. Further, the disclosure of the reference teaches forming a packet for transporting circuit data (full or partial frames) over a packet network by placing the first byte into the packet from the lowest number slot of the frame, the next packet from the next lowest slot, etc. This is repeated across frames until the packet is filled. In this manner, when the bytes are read out, the first byte is placed into the lowest numbered slot in the outgoing frame, the next byte is placed in the next lowest numbered frame, etc. IP networks do not appear to be explicitly disclosed.
Whatever the precise merits, features and advantages of the above cited references, none of them achieve or fulfills the purposes of the present invention. These and other objects are achieved by the detailed description that follows.